Sorry your daughter is struggling so much.
I'm hearing some unhelpful comments from the professionals that you might want to give some gentle pushback on behind the scenes. If you are in the US and your daughter is a minor, you are entitled to be able to get in touch with any provider and tell them of your concerns.
At an appt with her dietician a few weeks ago, dietician said she thinks daughter is doing really well. That made daughter very upset, as she obviously equates "doing well" with "being fat".
For this one, I might suggest phoning the dietician and mentioning what happened here and caution her against saying your daughter is doing well again. Does the dietician weigh her? Blind weighing could be an option at this point and no commentary on how she is doing from the dietitian. Just a smile and a thank you after she gets off the scale.
As far as this comment from the therapist:
She told me her therapist thought she was too "enmeshed
" with me, and I feel like now she's trying to establish some independence and identity of her own (which is great, healthy thing for her to do), and just the fact that I'm even here is troublesome to her.
Have you heard of Hilde Bruch? She was the psychoanalyst who worked on that enmeshment theory a very long time ago—like in 1973 or thereabouts. Before much of the modern research about eating disorders that we know about now which takes genetics and the fact that eating disorders are a brain based mental illness into account. In those days, it was believed that the parent, especially the mother, became "enmeshed" or too over involved with the child and that this in some way contributed to the eating disorder. And it all somehow had roots in early childhood. That led to Salvador Minuchin, a psychiatrist who passed away a few years ago, developing something called family systems therapy. It was important because despite everything it was the first time the power of the family was considered in eating disorder treatment. It is interesting to read about in a historical sense, however there have been so many advances since then that it is now generally understood that parents are part of the solution, NOT part of the problem and that "enmeshment" doesn't contribute to the eating disorder but in fact families who support regular mealtimes and full nourishment are more likely to see a positive outcome with this illness.
Unfortunately for us parents, there are still some therapists who seem to cling to this outdated way of thinking. So this brings up a pretty big red flag. This is a great way for your daughter's eating disorder to advocate for what it wants: for you not to require her to eat and for you not to feed her. Look you are already considering letting her make her own food while you make dinner for your husband and other child. This is exactly what the eating disorder would like because it will most likely allow your daughter to eat less while pushing you, the person who wants her to eat, away.
In your shoes I would make dinner for the whole family and have her join you to eat it, while keeping her out of the kitchen while you prepare it. Is it a coincidence that this discussion about "independence" is coming up around the time that she learns she is "doing well" ???(meaning she is gaining weight) It seems as though the eating disorder is trying to triangulate a way to eat less by getting you to back off supported by the therapist.
I can tell you that we had a dietitian who also started talking about independence and letting my daughter eat on her own when it was really too early, and I allowed her to go away on a trip with friends for 3 weeks and feed herself. A skeleton walked into my house when she arrived home. When we went to see the dietitian I was pretty peeved but kept my demeaner pretty low key and non critical. She told me to bring my daughter home and feed her and we never again had a discussion about her "independence" or letting her take more "control" over her food. We didn't have to because the next time I let her do it, many months later she was actually ready to try.
Typical teens don't mind eating dinner with their parents and having whatever is on the table and in the end the goal is to normalize eating. Kids with eating disorders do mind that. But there are several choices here: you can let her have more opportunity to feed herself for say, a week, and if she loses weight she also loses that privilege, or you can just insist that normal kids eat with their families and have her do that.
Since then I've tried to make vegetarian options for dinner and she rejects anything vegetarian that I cook for her. She just wants to control all her own food
This is also a pretty big red flag. She says she wants to be a vegetarian and then rejects the vegetarian food what you make?
Anyway I hope that this will give you some food for thought as they say, about how to proceed.